Fossil fuels are one of the world's leading sources of energy. However, these fuels are being irreversibly depleted at a more rapid rate than they were initially formed. Thus, there exists a continual need to derive newer and more efficient processes for converting crude oils into useable petroleum products.
The rising demand for oil and oil by-products has lead to the conversion of higher molecular weight crude oils into these desired products. One method of accomplishing this conversion process is by reducing the molecular weight of these heavy crude oils. One principle method utilized in reducing the molecular weight of hydrocarbons is referred to as "catalytic cracking". Generally, with this method, hydrocarbon feedstocks containing higher molecular weight hydrocarbons have their molecular weight reduced (i.e. "cracked") by being contacted under elevated temperatures with a cracking catalyst whereby producing light distillates such as gasoline.
In the catalytic cracking of hydrocarbon feedstocks, particularly heavy feedstocks, metals such as nickel, vanadium, iron, copper and/or cobalt present in the feedstocks become deposited on the cracking catalyst promoting excessive hydrogen and coke formations. Since the production of hydrogen and coke is inversely proportional to the production of usable by-products, these are undesirable products of a cracking process. Furthermore, although the cracking catalyst does undergo a regeneration process, the metal contaminants, which cause the excessive formation of hydrogen and coke, are not removed by conventional catalyst regeneration operation. Therefore, there exists a need to remove contaminating metals from cracking catalysts.
One method of removing part of the effects of these contaminating metals is through a process called metals passivation. As used hereinafter, the term "passivation" is defined as a method for decreasing the detrimental catalytic effects of metal contaminants such as nickel, vanadium, iron, copper and/or cobalt which become deposited on the cracking catalyst. Therefore, by passivating the contaminating metal deposits on cracking catalysts, the catalysts' life and desired product yields can be prolonged and increased respectively.
It is known that some of the metal deposits, which contaminate cracking catalysts, can be passivated to some degree by contacting the contaminated catalyst with various metal passivating compounds. One method of carrying out this process is by dispersing the selected metal passivating agent either directly into the hydrocarbon cracking reactor or into the hydrocarbon feed stream. Although there are many compounds which can, to some degree, passivate contaminating metal deposits, there is always a need for new, improved metal passivating agents. Therefore, it is an object of this invention to provide a metals passivation process which utilizes new, improved passivating agents.
Due to the increasing demand, of a limited supply of petroleum and other related products, if it were possible to increase the degree of converting higher molecular weight hydrocarbons to lighter distillates such as gasoline, by increasing the degree of passivating metal deposits, a substantial improvement in the art would be afforded. Thus, a further object of this invention is to provide novel, improved passivating agents for cracking catalysts.
Still a further object of this invention is to provide a modified cracking catalyst which provides high product yields and selectivity for gasoline and/or other higher-boiling hydrocarbon fuel.
Further objects, embodiments, advantages, features and details of this invention will become apparent to those skilled in the art from the following detailed description of the invention and the appended claims.